02/22/2013 12:36 EST | Updated 04/24/2013 05:12 EDT

Sex offender charged in teens' deaths found guilty

A B.C. Supreme Court justice has found a man with a history of predatory attacks on vulnerable girls guilty of two counts of criminal negligence causing death.

Martin Tremblay was charged in connection with the deaths of 16-year-old Kayla LaLonde and 17-year-old Martha Jackson, also known as Martha Hernandez, who had partied at his home the night before they died.

Tremblay was also found guilty of one count of obstruction of justice, while two charges of failing to provide the necessities of life were stayed Friday.

The court heard during the trial the teens' deaths were the result of overdosing on a combination of drugs and alcohol.

Lalonde was found dead on a Burnaby street after witnesses said she had been dumped from a van.

Jackson died after being rushed by ambulance from Tremblay's Richmond home.

Tremblay was previously convicted of five counts of sexual assault in 2002 and sentenced to 14 months. He was found guilty of giving drugs and alcohol to five aboriginal teenage girls and then videotaping his sex acts with them after they passed out.

In February 2010, Vancouver police took the extraordinary step of issuing a public plea for victims of Tremblay, after a protest on the Downtown Eastside by First Nations women who were concerned about Tremblay's upcoming release from custody.

In September 2011, police announced he was facing seven new charges for sexual assaults on young vulnerable women and girls.

Tremblay’s most recent trial began in October.